C++第三章习题

超、凢脫俗 2023-07-09 02:25 16阅读 0赞

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjA3ODk0_size_16_color_FFFFFF_t_70]

1.  这退格好使欸

#include <iostream>
    
    int main()
    { 
        using namespace std;
        cout << "Enter your height in inches (enter an integer):___\b\b\b";//英寸
        int inches;
        const int inch_per_feet = 12;//1英尺=12英寸
        cin >> inches;
        cout << inches << " inches is " << inches / inch_per_feet << " feet and " << inches % inch_per_feet << " inches.\n";
        return 0;
    }

Enter your height in inches (enter an integer):98_
    98 inches is 8 feet and 2 inches.

#include <iostream>
    int main()
    { 
        using namespace std;
        const int inch_per_feet = 12;
        const float meter_per_inch = 0.0254;
        const float pound_per_kg = 2.2;
        cout << "Enter your height in feet and inches, first enter the number of feet:\n";
        int height_feet, height_inch, height_inches;
        float weight_pound, weight_kg, height_meter;
        cin >> height_feet;
        cout << "Then the number of inches:\n";
        cin >> height_inch;
        height_inches = height_feet * inch_per_feet + height_inch;
        height_meter = height_inches * meter_per_inch;
    
        cout << "Your height is " << height_inches << " inches.\n";
        cout << "Now enter your weight in pounds:\n";
        cin >> weight_pound;
        weight_kg = weight_pound / pound_per_kg;
        cout << "Your BMI (Body Mass Index) is " << weight_kg / (height_meter * height_meter) << endl;
        return 0;
    }

Enter your height in feet and inches, first enter the number of feet:
    5
    Then the number of inches:
    2
    Your height is 62 inches.
    Now enter your weight in pounds:
    127
    Your BMI (Body Mass Index) is 23.2772

#include <iostream>
    int main()
    { 
        using namespace std;
        cout << "Enter a latitude in degrees, minutes, and seconds:\n";
        float degrees, minutes, seconds;
        const int min_per_deg = 60;
        const int sec_per_min = 60;
        cout << "First, enter the degrees:";
        cin >> degrees;
        cout << "Next, enter the minutes of arc:";
        cin >> minutes;
        cout << "Finally, enter the seconds of arc:";
        cin >> seconds;
        float deg;
        deg = degrees + (seconds / sec_per_min + minutes) / min_per_deg;
        cout << degrees << " degrees, " << minutes << " minutes, " << seconds << " seconds = " << deg <<
        " degress.\n";
        return 0;
    }

Enter a latitude in degrees, minutes, and seconds:
    First, enter the degrees:37
    Next, enter the minutes of arc:51
    Finally, enter the seconds of arc:19
    37 degrees, 51 minutes, 19 seconds = 37.8553 degress.

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjA3ODk0_size_16_color_FFFFFF_t_70 1]

#include <iostream>
    int main()
    { 
        using namespace std;
        long long secs;
        int day, hour, minute, second, day_, hour_;
        const int hours_per_day = 24;
        const int minutes_per_hour = 60;
        const int seconds_per_minute = 60;
        cout << "Enter the number of seconds:";
        cin >> secs;
        day = secs / (hours_per_day * minutes_per_hour * seconds_per_minute);
        day_ = secs % (hours_per_day * minutes_per_hour * seconds_per_minute);
        hour = day_ / (minutes_per_hour * seconds_per_minute);
        hour_ = day_ % (minutes_per_hour * seconds_per_minute);
        minute = hour_ / seconds_per_minute;
        second = hour_ % seconds_per_minute;
        cout << secs << " seconds = " << day << " days, " << hour
             << " hours, " << minute << " minutes, " << second << " seconds\n";
        return 0;
    }

Enter the number of seconds:31600000
    31600000 seconds = 365 days, 17 hours, 46 minutes, 40 seconds

5 错误示范（类型转换错误，还没写乘以100）

#include <iostream>
    int main()
    { 
        using namespace std;
        long long global, american;
        cout << "Enter the world's population:";
        cin >> global;
        cout << "Enter the population of the US:";
        cin >> american;
        cout << "The population of the US is " << float(american / global) << "% of the world population.\n";
        return 0;
    }

Enter the world's population:6898758899
    Enter the population of the US:310783781
    The population of the US is 0% of the world population.

正确版本,只改return前面最后一句

cout << "The population of the US is " << float(american) / float(global) * 100 << "% of the world population.\n";

Enter the world's population:6898758899
    Enter the population of the US:310783781
    The population of the US is 4.50492% of the world population.

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjA3ODk0_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200227153847636.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjA3ODk0,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjA3ODk0_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200227153900322.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjA3ODk0,size_16,color_FFFFFF,t_70